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Query: UMLS:C0034069 (pulmonary fibrosis)
 7,050 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulmonary fibrosis is an irreversible accumulation of connective tissue in the interstitium of the lung. The pathogenesis of pulmonary fibrosis is not well understood. Research on animal models and studies of human lung disease suggest the initiating events may be a combination of pulmonary injury and the recruitment of inflammatory cells, mainly macrophages. A number of well characterized cytokines, including TGF-beta, have been either found in the injured lung or produced by inflammatory cells removed from the lung. In an animal model of pulmonary fibrosis, TGF-beta production is increased prior to collagen synthesis and is mainly produced by alveolar macrophages. In advanced idiopathic pulmonary fibrosis, a human fibrotic lung disease, extensive TGF-beta deposition can be detected by immunohistochemical staining, primarily in epithelial cells in areas of lung regeneration and remodelling. This suggests that the pathogenesis of the progressive fibrosis characteristic of this lung disease may be an aberrant repair process.
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PMID:The role of TGF-beta in pulmonary fibrosis. 171 97

Alveolar macrophages are believed to be central in orchestrating the fibrotic response in interstitial lung disease (ILD). To test the hypothesis that macrophages from patients with ILD were dedicated to growth factor production and that this was independent of other indices of macrophage activation, we measured the mRNA of the B chain of PDGF and TGF-beta, as well as HLA-DR-alpha in alveolar macrophages from patients with ILD and from normal control subjects. When alveolar macrophages were examined immediately after lavage, cells from patients with ILD had increased PDGF(B) but similar TGF-beta and HLA-DR-alpha mRNA when compared with control subjects. Discoordinate regulation of these genes was observed when alveolar macrophage PDGF(B) mRNA increased while TGF-beta and HLA-DR-alpha mRNA decreased after culture for 24 h. This response was not disease-related as these changes were similar in cells from patients with ILD and from control subjects. Because a lymphocytic alveolitis is present in many cases of ILD, we asked whether interferon gamma (IFN-gamma) modulated the activation of these genes. In both the patients and the control subjects, PDGF(B) and HLA-DR-alpha, but not TGF-beta, mRNA were increased after incubation with IFN-gamma. These results indicate that PDGF(B) mRNA may be increased in alveolar macrophages in ILD and that PDGF(B), TGF-beta, and HLA-DR-alpha are independently regulated genes in alveolar macrophages, but that IFN-gamma increases both PDGF(B) and HLA-DR-alpha mRNA. We speculate that IFN-gamma induced PDGF(B) gene activation may be an important mechanism by which lymphocytes promote pulmonary fibrosis.
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PMID:Pathogenesis of pulmonary fibrosis in interstitial lung disease. Alveolar macrophage PDGF(B) gene activation and up-regulation by interferon gamma. 189 43

Interleukin-1 (IL-1) is a cytokine with diverse biological activities. It can serve as a fibroblast (FB) growth factor which involves in the development of pulmonary fibrosis. IL-1 receptor antagonist (IL-1ra) can compete with IL-1 for occupancy of surface receptors of target cells without agonist effect. In order to find a new method to treat pulmonary fibrosis, we investigated the effect of recombinant human IL-1ra on the development of pulmonary fibrosis by evaluating collagen content, histological change, and TGF-beta mRNA expression in the rats bleomycin-induced pulmonary fibrosis. The results indicate are that there are no significant difference between the IL-1ra treated group and the control group.
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PMID:[The effect of IL-1 receptor antagonist on bleomycin-induced pulmonary fibrosis]. 752 98

The role of bombesin was investigated in the course of the pulmonary inflammation and fibrosis (PF) elicited by the intratracheal (IT) or intravenous (i.v.) administration of bleomycin in mice. Bleomycin-induced alveolitis was associated with an accumulation of cells, presumably macrophages, containing bombesin, as evidenced by immunohistochemistry. Administration of bombesin by an osmotic minipump implanted IP, at a rate of 6 micrograms/h, decreased the lung hydroxyproline evident 15 days after IV or IT administration of bleomycin. In contrast, antibombesin monoclonal antibody 2A11 (mAb) increased the lung hydroxyproline content after IT administration of bleomycin. In addition, the mortality of bleomycin-injected mice was increased by the anti-bombesin mAb. Bombesin administration induced an increase, and anti-bombesin mAb induced a decrease, in the number of macrophages recovered from the bronchoalveolar lavage. Administration of bombesin did not change the mRNA levels of TNF-alpha, TGF-beta, and PDGF, as seen on Northern blots made with the lung RNA. Pulmonary platelet trapping, which was increased by a bleomycin injection, was decreased by an infusion of bombesin as demonstrated by the distribution of 111In-labeled platelets. This study indicates that bombesin act as an inhibitor of the development of pulmonary fibrosis, possibly by decreasing pulmonary platelet trapping.
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PMID:Bombesin down modulates pulmonary fibrosis elicited in mice by bleomycin. 753 40

Bleomycin-induced pulmonary fibrosis is associated with increased lung transforming growth factor-beta (TGF-beta) gene expression, but cellular localization of the source of this expression has not been unequivocally established. In this study, lung fibrosis was induced in rats by endotracheal bleomycin injection on day 0 and, on selected days afterwards, lungs were harvested for in situ hybridization, immunohistochemical and histochemical analyses for TGF-beta 1 mRNA and protein expression, and cell identification. The results show that control lungs express essentially no detectable TGF-beta 1 mRNA or protein in the parenchyma. Before day 3 after bleomycin treatment, scattered bronchiolar epithelial cells, mononuclear cells, and eosinophils expressed elevated levels of TGF-beta 1. Between days 3 and 14, there was a major increase in the number of eosinophils, myofibroblasts, and fibroblasts strongly expressing TGF-beta 1 mRNA and protein. TGF-beta 1-producing cells were predominantly localized within areas of injury and active fibrosis. After day 14, the intensity and number of TGF-beta 1-expressing cells significantly declined and were predominantly found in fibroblasts in fibrotic areas. The expression of TGF-beta 1 protein was generally coincident with that for mRNA with the exception of bronchiolar epithelial cells in which strong protein expression was unaccompanied by a commensurate increase in mRNA. The study demonstrates that myofibroblasts, fibroblasts, and eosinophils represent the major sources of increased lung TGF-beta 1 expression in this model of pulmonary fibrosis.
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PMID:Cellular localization of transforming growth factor-beta expression in bleomycin-induced pulmonary fibrosis. 754 34

The development of bleomycin-induced pulmonary fibrosis in rats was studied over a period of 21 d after an intratracheal instillation of bleomycin. The expression of three small proteoglycans (biglycan, decorin, and fibromodulin), collagen III and TGF-beta 1 was studied by RNA-transfer blot analysis. The proteoglycans were also studied by SDS-polyacrylamide gel electrophoresis and Western blots. TGF-beta 1 mRNA increased threefold already on day 3 and remained elevated until day 10. After the increase of TGF-beta 1 mRNA the messages for biglycan and collagen III steadily increased to reach a maximum 10 d after bleomycin instillation. The mRNA for biglycan increased maximally fourfold and that of collagen III 2.5-fold. Decorin mRNA, in contrast to biglycan decreased and reached 20% of control on day 10. The message for fibromodulin remained constant throughout the study period. The amounts of biglycan and decorin in the tissue changed in accordance with the mRNA levels. The results corroborate and extend previous in vitro studies concerning the effect of TGF-beta 1 on the metabolism of small proteoglycans and show that these macromolecules are regulated differently also in vivo. The marked alterations of biglycan and decorin during the development of fibrosis suggests that these proteoglycans have a regulating role in this process.
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PMID:Altered expression of small proteoglycans, collagen, and transforming growth factor-beta 1 in developing bleomycin-induced pulmonary fibrosis in rats. 768 61

Susceptibility of mice to the induction of pulmonary fibrosis by bleomycin sulfate is inbred strain dependent, with C57BL/6 mice exhibiting high sensitivity to the drug and BALB/c mice demonstrating a resistant phenotype. The lungs of bleomycin treated C57BL/6J and BALB/cBy mice were analyzed for their mRNA expression level of a panel of cytokines using a semi-quantitative polymerase chain reaction (SQ-PCR) assay. Transforming growth factor-beta 1 (TGF-beta 1) mRNA was found to increase sevenfold by 5 days after bleomycin treatment of C57BL/6J (sensitive) mice. BALB/cBy (resistant) animals demonstrated a lower level of TGF-beta 1 mRNA induction, approximately threefold, after bleomycin administration. Analysis of interleukin-1 beta (IL-1 beta) mRNA levels also revealed a difference between the two strains, with BALB/cBy mice expressing approximately fourfold higher IL-1 beta mRNA levels than C57BL/6J mice. This result suggested possible protection by IL-1 beta. Analysis of (C57BL/6JxBALB/cBy)F1 hybrids, which are shown in this report to be sensitive to bleomycin-induced fibrosis, revealed a high IL-1 beta mRNA level, similar to that in the resistant parent. Thus, the observed strain variation in the level of IL-1 beta mRNA is not associated with differences in susceptibility to the induction of pulmonary fibrosis. In contrast, strain variation in interleukin-6 (IL-6) mRNA levels was observed that was completely concordant with the segregation of susceptibility phenotypes between the parental and F1 strains. This result indicates a possible association between sensitivity to bleomycin-induced fibrosis and inducibility of IL-6 mRNA upon drug treatment. Analysis of TGF-beta 2, interferon-gamma, interleukin-2, interleukin-3, and interleukin-4 (IL-4) mRNA showed no detectable strain variation in steady state mRNA levels in the lung as a consequence of bleomycin treatment. In contrast, the level of IL-4 receptor mRNA was induced to a higher degree in both sensitive groups (C57BL/6J and F1) than in resistant mice (BALB/cBy). Therefore, modulation of the IL-4 response, not at the level of IL-4 but through regulation of the IL-4 receptor, may play a role in pulmonary fibrogenesis.
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PMID:PCR analysis of cytokine induction profiles associated with mouse strain variation in susceptibility to pulmonary fibrosis. 769 32

The carcinogenic effects of crystalline silica in rat lungs were extensively demonstrated by many experimental long-term studies, showing a marked predominance for adenocarcinomas originating from alveolar type II cells and associated with areas of pulmonary fibrosis (silicosis). In contrast with its effects in rats, silica did not induce alveolar type II hyperplasia and lung tumors in mice and hamsters, pointing to a critical role for host factors. Using these animal models, we are investigating the role of cytokines and other cellular mediators on the proliferation of alveolar type II cells. Immunohistochemical localization of TGF-beta 1 precursor in alveolar type II cells adjacent to silicotic granulomas was shown to occur in rats, but not in mice, and hamsters, suggesting a pathogenetic role for this regulatory growth factor. Recent investigations in our laboratory on the biologic mechanisms of crystalline silica included determination of anionic sites on crystalline silica surfaces by binding of the cationic dye Janus Green B; binding of crystalline silica to DNA, demonstrated by infrared spectrometry; production of oxygen radicals by crystalline silica in aqueous media; induction of DNA strand breakage and base oxidation in vitro and its potentiation by superoxide dismutase and by hydrogen peroxide; and induction by crystalline silica of neoplastic transformation and chromosomal damage in cells in culture. On the basis of these in vitro studies, we propose that DNA binding to crystalline silica surfaces may be important in silica carcinogenesis by anchoring DNA close to sites of oxygen radical production on the silica surface, so that the oxygen radicals are produced within a few A from their target DNA nucleotides.
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PMID:Mechanisms of carcinogenesis by crystalline silica in relation to oxygen radicals. 770 91

Sarcoidosis is a chronic inflammatory disease of unknown cause characterized by the formation of nonnecrotizing granulomas in affected tissues, most notably the lungs. Granuloma healing may result in pulmonary fibrosis and respiratory impairment in some patients. Transforming growth factor-beta 1 (TGF-beta 1) is a potent cytokine that promotes fibrosis by enhancing the synthesis of extracellular matrix components, including fibronectin and the alpha 5 beta 1 fibronectin receptor. The role of TGF-beta 1 in promoting lung fibrosis in the setting of pulmonary sarcoidosis has not yet been investigated. Accordingly, we determined the extent and distribution of TGF-beta 1 in lung tissue obtained from seven patients with clinical and histologic features of pulmonary sarcoidosis. The tissue distributions of TGF-beta 1, the TGF-beta 1 binding proteoglycan decorin, fibronectin, and the alpha 5 beta 1 fibronectin receptor were assessed immunohistochemically. In all cases, the epithelioid histiocytes comprising nonnecrotizing granulomas of pulmonary sarcoidosis contained abundant TGF-beta 1. We further demonstrated decorin, fibronectin, and the alpha 5 beta 1 fibronectin receptor within nonnecrotizing granulomas and in the fibrous tissue surrounding the lesions. TGF-beta 1 staining was also observed in bronchiolar epithelial cells, hyperplastic Type II pneumocytes, and occasional alveolar macrophages. This study demonstrates enhanced tissue localization of TGF-beta 1 and related extracellular matrix proteins associated with the nonnecrotizing granulomas of pulmonary sarcoidosis. Through its actions on matrix protein synthesis, TGF-beta 1 may modulate the fibrotic repair process accompanying granuloma healing in sarcoidosis.
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PMID:Immunohistochemical localization of transforming growth factor-beta 1 in the nonnecrotizing granulomas of pulmonary sarcoidosis. 811 83

Fibroblast heterogeneity is known to exist in chronically inflamed tissue such as pulmonary fibrosis (IPF) and scleroderma. We have previously shown differences in proliferation rates in primary lines and cloned lines of fibroblasts derived from IPF tissue compared with normal lung. In this study, we report that cell lines derived from fibrotic tissue demonstrate anchorage-independent growth in soft agarose culture whereas normal lung fibroblast lines do not. We also show that fibroblast lines derived from neonatal lung tissue form colonies at about the same frequency as the fibrotic cells. Colonies from both fibrotic and neonatal lines were shown to be positive for vimentin, laminin, fibronectin, fibronectin receptor, beta-actin, and tropomyosin by immunohistochemistry but were negative for desmin, keratin, Factor VIII, alpha-smooth muscle cell actin, and tenascin. Treatment with cytokines TGF-beta and PDGF or with corticosteroid modified the colony-forming capacity of fibrotic and neonatal cell lines, however, none of these treatments induced normal lung cell lines to form colonies. The presence of cells in adult fibrotic tissue with growth characteristics similar to those exhibited by neonatal cells is further evidence of fibroblast heterogeneity and suggests newly differentiated fibroblasts may be prevalent in fibrotic tissue and contribute directly to the matrix disorder seen in this disease.
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PMID:Anchorage-independent colony growth of pulmonary fibroblasts derived from fibrotic human lung tissue. 816 56


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